<style>
#canvas2 { width: 800px; height: 600px; display: block; }
</style>
<canvas id='canvas1'></canvas>
<blockquote cite="https://stackoverflow.com/questions/44768471/how-to-achieve-moving-line-with-trail-effects">
  <p>How to Achieve Moving Line with Trail Effects</p>
</blockquote>

<canvas id='canvas2'></canvas>
<blockquote cite="https://stackoverflow.com/questions/56841018/webgl-droste-effect">
  <p>WebGL Droste effect</p>
</blockquote>